First Principles Study of Gas Molecules Adsorption on Monolayered β-SnSe

For the purpose of exploring the application of two-dimensional (2D) material in the field of gas sensors, the adsorption properties of gas molecules, CO, CO2, CH2O, O-2, NO2, and SO2 on the surface of monolayered tin selenium in beta phase (beta-SnSe) has been researched by first principles calculation based on density functional theory (DFT). The results indicate that beta-SnSe sheet presents weak physisorption for CO and CO2 molecules with small adsorption energy and charge transfers, which show that a beta-SnSe sheet is not suitable for sensing CO and CO2. The adsorption behavior of CH2O molecules adsorbed on a beta-SnSe monolayer is stronger than that of CO and CO2, revealing that the beta-SnSe layer can be applied to detect CH2O as physical sensor. Additionally, O-2, NO2, and SO2 are chemically adsorbed on a beta-SnSe monolayer with moderate adsorption energy and considerable charge transfers. All related calculations reveal that beta-SnSe has a potential application in detecting and catalyzing O-2, NO2, and SO2 molecules.